1. Field of the Invention
The invention pertains to a method for forming a variety of blended composition board products including particleboard, fiberboard, waferboard, oriented strandboard and layer particleboard and the novel board products resulting therefrom as the result of separation of one portion of the solid components of the composition board ingredients and the separate coating of that portion of the composition board component with an adhesive to employ that portion as an adhesive carrier and then combining that coated component with the remaining solid composition board components. Typically the coating of the first portion of the solid component of the composition board represents the smaller portion in volume and particle size and in the preferred applications represents the utilization of fines as an adhesive carrier for blended composition board products by the separating and coating the fines with resins, glues and/or waxes prior to mixing the coated fines with the remaining larger particles of the blended composition board to provide novel products having a more homogeneous consistency and better cohesive bonded properties than prior art composition board products without the adhesive carrying fines.
More particularly the invention pertains to a process and resulting novel products that include precoated fines of a particle size of about 10 to 40 mesh and smaller which operate as an adhesive carrier for novel composition board products that eliminate resin spots and nonuniform gluing of particles in the blended composition board. The present process and resulting products provide a more uniform distribution of adhesives or binders in the novel homogeneous composition board products by employing the coated fines as a nucleus for attaching to larger particles to provide a more uniform and homogeneous product having superior cohesive and bonding characteristics for the same or less resin content than the prior art.
2. Description of the Prior Art
The prior art blending tools, blenders and processes have been directed toward providing a more homogeneous and better blended composition board product. Various types of blenders and related processes have been employed to achieve a more homogeneous and better bonded product. These methods and apparatus have usually been in the direction of modifying blending apparatus to become larger, longer and more sophisticated as a means for providing a more homogeneous and better cohesively bonded product.
One such prior art apparatus for applying adhesive to fibrous material includes Lodige, et al, U.S. Pat. No. 4,143,975 which provides an apparatus for more efficiently adding resin and gluing the components together by the utilization of larger and more complicated blenders. Such prior art blenders have defined gluing zones and mixing zones with each zone having different types of tools to provide different processing zones in the blender designed to treat all the wood and attempt to place all the resin or glue on all the wood. Such long, large diameter blenders provide specialized functions for the mixing and attempt to provide a more uniform application of glue to the mixed components to provide composition boards of a more homogeneous and uniform composition.
The Lodige, et al, U.S. Pat. No. 4,143,975 like the other prior art mixing and blending apparatus and methods are based upon the prior separation and discarding the fines from the components of the composition board since fines have heretofore generally been considered as undesirable components of composition board products. Fines are generally believed to rob the resin from the larger components of the blended mass and result in resin soaked fines aggregates and poorly bonded products. Once the fines have been removed the object of such prior art blenders and processes is then to get all the glue on all the wood in a single blender for blending all the solid constituents in an aggregate mass.
The present method unlike the Lodige, et al, U.S. Pat. No. 4,143,975 prior art does not mix the entire mass of composition board components together and apply glue or resins and waxes to the composition in separate mixing zones and gluing zones within a single composition board blender. In contrast to such prior art the invention separates the smaller particles or fines from the larger particles and then separately coats the smaller particles in a separate blender to provide a separate blended composition of precoated smaller particles which act as a resin carrier for the remaining components of the composition board. The precoated smaller particles or fines are then united and mixed in a second blender or mixer to provide a composition board having a more homogeneous and cohesive aggregate than heretofore available in the prior art.
The combination of the previously coated smaller particles or fines with the larger and preferably uncoated components of the composition board products of the invention provides a more uniform and cohesive final product than the prior art. The invention also unlike the prior art contemplates the use of fines, that are typically of a particle size of about 10 to 40 mesh or smaller. In the preferred application fines of a particle size of 20 to 40 mesh and 40 mesh and below that were typically discarded in the prior art processes are now utilized as a coated resin carrier to then be mixed with the remaining and typically uncoated larger solid components of the composition board product.
The prior art has generally in the preparation of composition board products also sought to apply all the resin or glue on all the components in a single mass resulting in blenders of greater length and diameter. Some of these methods have relied upon complicated systems for spraying and atomizing resins and increasing the viscosity of the resin along with the utilization of complicated tools for the application of glues and resins to the particles. These prior art methods of mixing in a single mass after the removal of fines has sought a more homogeneous mixture of components to eliminate resin spots and the poor cohesive nature of composition board in which all the glue has not been put on all of the wood components.
To further these objectives of the prior art it was also believed necessary to screen out or remove the fines and discard the fines as waste products since the fines rob the glue or resins from the larger particles thereby resulting in composition board of inferior qualities and significantly increasing resin consumption which typically represents the most expensive component of composition board. The invention in contrast to such prior art utilizes, instead of discards the fines as a resin carrier by precoating the fines in a separate high intensity blender and then combining the resin coated fines with the remaining components of the composition board in a conventional blender or an optimized mixer.
Prior art such as Vasshth, U.S. Pat. No. 3,930,089 forms a resin mass from rice hulls which is then placed in a hot press and subjected to heat and pressure to provide a layered board. This prior art while utilizing a previous waste product does not employ the process of the invention or the novel products of the invention by separating fines and utilizing the fines as a resin carrier for subsequent mixing in a blender with the larger particles of the composition board to provide a blended as opposed to a layered or laminated product of such prior art. The invention also in contrast to the prior art utilizes the fines of the composition board products and does not employ rice hulls from which the fines have been removed. The invention provides blended uniform homogeneous Composition board products having fines evenly distributed throughout the product to provide a more homogeneous and superior cohesive product than heretofore available in the prior art.
The prior art of blended composition board products including particleboard, medium density fiberboard, waferboard, oriented strandboard and number 3 layered particleboard have heretofore all utilized traditional manufacturing process in which the fines have first been removed and discarded before blending the composition board products. The fines have been removed in the belief fines rob the resin when blended together with the larger components of the blended composition board product and result in resin balls and clumps and a nonhomogeneous product. In spite of the removal of fines, resin spots and poor distribution of resin has remained a problem. In response the prior art has sought blending machines of more sophisticated and complicated design that are generally of larger size to solve the problem of providing a more uniform composition having better cohesive qualities.
Typically such prior art blender machines have increased in size to 3 feet or more in diameter and to more than 14 feet long and have increased in internal complexity in having a plurality of mixing, resin addition and blending zones and tools of varying design in each of the zones. It will also be recognized by those skilled in the art that the number, type and complexity of design of the tools also increase as the diameter of the machine increases since a smaller and more compact machine having a smaller diameter can provide greater mixing capabilities by operating at a higher RPM. Similarly the approach of the prior art of getting all the resin on all the wood in a single blended mass has increased the number of stations located in the prior art blenders as well as the complexity of those stations in spraying or otherwise adding resin in the blender. The effort to increase blending efficiency has also resulted in reducing the viscosity of the resin in an effort to provide a more uniform distribution in the prior art blending processes.
The invention unlike the prior art does not seek to utilize larger diameter and longer machines to increase the efficiency of the blended components of the composition board product but instead employs a novel method of not blending all the components in a single mass and in utilizing instead of discarding the fines of composition board products as a resin carrier and in increasing rather than decreasing resin viscosity. The method of the invention first separates the components of composition board into two groups. The first group is then judiciously coated with an adhesive or resin which may or may not be mixed with waxes. The first coated group operates as a resin carrier to reduce, if not entirely eliminate resin spots in the final product. The first group is then mixed or blended with the second group of components which typically is not coated with an adhesive. In the preferred application of the invention the first group represents the smallest component in terms of particle size and volume and preferably are fines that typically had previously been discarded in the prior art. The fines are then blended with resin in a high intensity blender and then subsequently blended in a second blender to blend the resin coated fines with the larger particles of the composition board product.
The second blending step is preferably without the addition of more resin since the resin coated fines when mixed in proper proportions with resin operate as the binding nuclei for the remaining solid components to reduce total resin used, remove the formation of resin spots and provide a new and more homogeneous composition board products. The advantages of the present process provide further advantages in not only reduced cost, shape and size of the equipment but also results in novel products as will be discussed hereinafter in greater detail.